This invention relates to tamper proof (or "tamper evident") container assemblies, and more specifically, to a container and lid assembly in which the lid is effectively locked to the container body prior to initial use by means of a removable tear strip integrally formed with the lid, and which nevertheless permits repeated reapplication and removal of the lid to the container body. At the same time, any tampering with the cover to gain access to the interior of the container will be immediately apparent.
Numerous attempts have been made in the container industry and specifically with respect to consumer oriented foodstuffs, medicines, etc. to prevent potentially harmful tampering with the contents of such containers. It is well known, for example, to heat seal a thin foil disk about the container opening prior to assembly of the lid. This approach, while successful to a large extent, nevertheless involves the addition of another component to the assembly, i.e., the foil disk, and related assembly procedures and associated costs.
Other attempts to provide effective tamper proof mechanisms in container assemblies are well documented in the patent literature. U.S. Pat. No. 4,966,294, for example, discloses a tamper evident closure for a wide mouth container wherein rim segments are formed in the skirt portion of the container lid and are arranged so that upward lifting force applied against the lid flange will cause breakage to occur at opposite ends of the flange, and a continued upward pulling on the flange will result in a pair of tear lines in the lid to facilitate removal of the lid.
In U.S. Pat. No. 2,383,760, a closure for a container includes a flat upper surface in the peripheral depending skirt portion around which is adhesively secured a strip which extends below the container flange and includes a bent marginal flange portion extending upwardly and inwardly from the bend. The flange is a continuous, smooth flange which, after insertion over the upper portion of the container, will snap into locking engagement with the flange. The marginal portion of the sealing strip is provided with a strip of adhesive so that the marginal portion will be cemented to the inside face of the container flange. No means are provided, however, for facilitating the easy removal of the closure. In fact, it is stated that when a container is opened, the cover will be disposed of, apparently because it will be damaged or destroyed in the opening operation.
In U.S. Pat. No. 1,955,865, container closures are disclosed which are formed with depending skirt portions and integral circumferentially spaced bent tab portions. These tab portions are designed to cooperate with complementary circumferentially spaced tabs formed on the periphery of the container side wall. Locking of the lid to the container is achieved by pressing the closure down over the tabs and rotating it so that the tabs will lie behind respective tabs on the container side wall. Fairly rigid disks are required to maintain the locking engagement between the cover and the container.
Other tamper proof constructions are disclosed in U.S. Pat. Nos. 3,044,610; 3,997,056 and 4,602,718.
These prior efforts are characterized by rather complex, and therefore costly, arrangements which are not fully satisfactory in all respects.
It is the principle object of the present invention to provide a simple, low cost yet effective tamper proof or tamper evident container assembly which permits repeated application and removal of the container lid even after one time use of the tamper evident mechanism by the consumer upon initial opening.
In an exemplary embodiment of the invention, there is provided a container and lid assembly including an open ended container body having a bottom wall and a peripheral side wall. The upper end of the peripheral side wall is provided with a radially outwardly extending flange, preferably formed by outward rolling and subsequent compression of the upper free edge of the peripheral side wall in a manner well known to those skilled in the art.
The container lid is formed with a top wall and an annular depending skirt which is formed with an annular line of weakening extending about the entire skirt at a location intermediate upper and lower ends of the skirt, and preferably toward the lower end.
After the container has been filled, the lid is applied and the free end of the skirt is mechanically tucked under the lower edge of the rim or seam at the upper end of the container body by a conventional curling iron. This mechanical curling or tucking operation causes the lower free end of the skirt to be bent around the lower end of the container rim to thereby lock the lid to the container body. In a preferred arrangement, a small portion of the lower edge of the skirt is left untucked to thereby provide a gripping area to permit the user to tear away the lower end portion of the skirt by reason of the annular line of weakening. Once this "tear strip" has been removed, the lid may be simply and easily lifted from the container body. Because of the relative length of the skirt left intact after removal of the tear strip portion, the lid may be effectively and repeatedly used by the consumer. At the same time, since the tear strip must be at least partially removed or otherwise deformed to allow separation of the lid from the container, any tampering with the container prior to its initial use will be immediately apparent from visual inspection.
Accordingly, the present invention provides a significant improvement over prior art tamper proof containers, and particularly those which result in the effective destruction of the lid during the initial opening of a container.
The tamper proof assembly of this invention thus provides the following advantages: 1) the tamper proof mechanism is integrally incorporated into the lid; 2) the previously required foil disk is eliminated; 3) a reclosing feature for the lid is retained; and 4) the assembly of this invention can be utilized by, for example, food stuffs distributors, with only minor modifications and/or additions to existing equipment.
In its broader aspects, therefore, the invention relates to tamper proof container assembly comprising an open-ended container body having a bottom wall and peripheral side wall, the side wall having an upper rim protruding radially outwardly of the peripheral side wall; a reusable lid having a top wall and a depending skirt, the skirt having a free end, a major portion of which is tucked under the upper rim to thereby lock the lid to the container body; and wherein the depending skirt is further provided in a lower portion thereof with a line of weakening extending annularly about the skirt portion to thereby define an annular tear strip inclusive of the free end so that upon removal of the tear strip, the lid may be removed from the container.
In another aspect, the invention relates to a tamper proof container assembly comprising an open-ended container body having a bottom wall and a peripheral side wall having a rim flange at an upper edge thereof; a reusable lid having a top wall and a depending skirt, the depending skirt incorporating first means for locking the lid to the container body, and second means for facilitating removal of the first means so as to allow removal of the lid from the container body without destroying the lid.
In a related aspect, the invention concerns a process for assembling a tamper proof container assembly including a container body having a bottom wall and a peripheral side wall including a radially outwardly projecting rim at an upper end thereof, and a reusable lid having a top wall and a depending skirt, the depending skirt having a line of weakening formed therein extending annularly around the skirt intermediate an upper end and a lower free edge thereof to thereby define a removable tear strip; the method comprising the steps of:
a) filling the container body with contents; PA1 b) applying the lid to the container body; and PA1 c) tucking a substantial portion of the lower free edge under the rim.
Additional objects and advantages of the invention will become apparent from the detailed description which follows.